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Need IF transformer , 57 Philco Auto radio. - Printable Version

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Need IF transformer , 57 Philco Auto radio. - Guest - 09-20-2009

I'm restoring a 57 Studebaker Hawk and have the radio out and on my bench.
I replaced the electrolytics and the vibrator buffer cap. Got a clean +250 volts
out of the power supply-oh Joy! But--- when I wired into the tuner, the voltage dropped
way down. Removed all the tubes and still too much load. A previous repair guy had
put a red X on one of the 455 Khz IF cans and I suspect a short. I don't have schematic since
no ID on the chassis but looks like other 50's Philco's I have repaired. Question is
"Where can I buy a replacement IF can" I don't have any parts radios to scavenge.
Thanks,
A Newbie--

DIck Curtis
Santa Barbara Ca

Re: Need IF transformer , 57 Philco Auto radio. - BILL - 09-22-2009

I believe you'll find that radio is a DELCO Studebaker quit buying it's radios from Philco ,I think, about 50 or 51 one of those years it's possible to find radios both built by Philco and Delco for Studebaker, If this is an original 57 Studebaker I have the Delco service manual and most likely the parts you need I think I'd look first on something else being the problem ,have you another power supply? Disable your power supply and aply 250 volt to your B+ most of the problems are in the power supply on these old radios, also check the voltage on your IF the primary will have the high voltage the secondary will be low , I had a 56 Ford radio{MOTOROLA} that checked out OK with no power with power it would leak high voltage to the secondary, replacing the IF took care of it , but that is a rare problem, usually you can see and hear an IF ark if they are shorted, I have found on these two piece Delcos 55-57 Chevy is almost the samething the lead between the two units is shealded with a metal covering the fabric coated wire will become fraded and short out , check that also: BILL

Re: Need IF transformer , 57 Philco Auto radio. - Guest - 09-23-2009

Bill,
Thanks you for the reply. The power section of the radio appears OK now that I have
replaced the filter and buffer caps. B* at 250 volts solid until I connect to the tuner. Since I removed all
tubes, the partial short is somewhere in the passive elements. I suspect the IF because of the red X
marked on the can, probably by some past repair guy. I'm not sure how to check the IF transformer.
Guess I'll try a digital ohmmeter to see if the primary is shorted to the secondary. Thanks for
the Delco vs Philco tip. I assumed since the four 50 & 51 Stude radios I previously fixed were Philco, that
this one was also. I'll check around more this weekend regards the shield short possibility.
...Dick

Re: Need IF transformer , 57 Philco Auto radio. - BILL - 09-24-2009

I believe I've seen this red X on other GM radio IF cans , I think this could be something the factory put there , I do about 100 old Chevy + GMC radios for a vintage truck parts supplyer a year, I think a voltage check might be the way to find a shorted IF can as the voltage I've seen will sometimes jump from the primary to secondary, and not show up with a continuity check , The more I think about it I'd check that shield from the power supply to RF ,GOOD LUCK, BILL

Re: Need IF transformer , 57 Philco Auto radio. - Don Lind - 09-24-2009

1. Are you sure the IF is 455 KHz?

2. Is there a part number on the can? If it begins with 32-XXXX, it is a Philco number.

3. Is it the first (input) or second (output) IF can?

I should have something that will work. There are plenty around.

Re: Need IF transformer , 57 Philco Auto radio. - Guest - 09-25-2009

Thanks again. I'll work on the radio this weekend. I really need a schematic. What model
number should I try to find and download for the Delco ?
....Dick

Re: Need IF transformer , 57 Philco Auto radio. - Guest - 09-25-2009

Good news. I found the radio iD. It is a Delco 311-HS. The suspect IF can is next to the 12AV6
socket so I suspect it is the second IF. I'll check out the voltage cable and look for a schematic
this afternoon.
....Dick

Re: Need IF transformer , 57 Philco Auto radio. - Guest - 09-25-2009

i couldn't find the schematic with the serial number 311-HS, but found a place
on the RF chassis where AC2748 was written. At SAMS,with this ID, it came up
Studebaker, so I think I finally have a chance of getting the schematic, Sent them
$7.00 so I should get it as a download.
I checked for a short between the two voltage leads enclosed in the shield--was OK.
....Dick